1. Field of the Invention
This invention relates to field of check valves and, more particularly, to a dual plate check valve incorporating a stop pin assembly, with the stop pin assembly preventing valve flappers from pivoting beyond a predetermined position.
2. Description of the Related Art
Check valves are one-way valves that permit a fluid to flow in one direction but not in the other direction. They come in a variety of sizes, shapes, and types and are usually self-controlling, meaning that the flow of the fluid itself will typically control the opening and closing of the check valve. They are often used in systems that utilize pumps to pump the fluid through piping or other similar vessels; a heart valve (natural or man-made) is one example of a check valve.
A certain type of check valve, sometimes referred to as a swing check valve or tilting disc check valve, utilizes one or more movable discs, sometimes referred to as “flappers”, to block the reverse flow of fluids. In a typical arrangement, the flapper is hinged on an axis of some kind, such as a hinge pin. In a two-flapper (dual-plate) arrangement, the hinge pin is centrally located with each flapper pivoting on the hinge pin towards each other like the wings of a butterfly.